Hate to spoil an otherwise good article, but it was the "anti-establishment" films of the 70s,

I don't know that you'd call Patton, True Grit, Dirty Harry, the French Connection and the Exorcist "anti-establishment" unless you are marking the very good case that the establishment was the left. Granted there was gore and bad words in those movies, but all espoused conservative values.

And actually, the top grossers in 1970-- Love Story and Airport -- were rather uncontroversial.